Amperometric ammonia sensors for low detection limit with BaZr(1-x)YxO3-δ proton electrolytes

Abstract

• BaZr 1-x Y x O 3-δ proton conductors were used as electrolyte in solid-state NH 3 sensors. • Electrolysis was proposed to detect ammonia by measuring the proton migration in BZY electrolytes. • The lowest detection limit of the amperometric NH 3 sensor can be 500 ppb. Ammonia (NH 3 ) sensor is a critical part in the selective catalytic reduction (SCR) system for the reduction of oxynitride emission. Here, novel amperometric NH 3 sensors are proposed based on BaZr (1-x) Y x O 3-δ (BZY, x = 0.1, 0.2, 0.3, 0.4) proton electrolytes. The influence of yttrium content on the structure, morphology and conductivity of BZY electrolytes is investigated systematically. Benefiting from the best conductivity of BaZr 0.8 Y 0.2 O 3-δ (BZY20) among these electrolytes, the sensor with the BZY20 electrolyte exhibits a low detection limit of 0.5 ppm at a relative low working temperature of 350℃. Furthermore, the sensor shows the highest sensitivity, good selectivity and repeatability to NH 3 . This work opens the way for the promising application of solid-state NH 3 sensor for low detection limit at low working temperatures.